Last week, Facebook started sending out mysterious invitations to press members via snail mail for a June 20th event. At the time, no one knew what it was planning to unveil at the presser, since it’s already taken the wraps off its Home project.

Today, though, it looks like we finally have our answer. According to a new report from AllThingsD, the rumors are true—Instagram has been working on a new video sharing service. And Facebook is going to show it off during Thursday’s event…

“Instagram plans to release a video product this Thursday at a press event at Facebook’s headquarters, according to multiple sources familiar with the matter, marking the first time the robust, 100-million user network will stray from being strictly a photo-sharing app and dive head first into the world of moving pictures.”

Isaac says that while details of the product have been kept under wraps, his sources have said that Facebook is seeking to differentiate itself from Vine. Twitter’s video sharing network has managed to gain considerable traction in the video space.

As we wrote earlier in a report on today’s update to the Vine app, the 6-second video creator has become extremely popular with users. The company says there are over 13 million people using the app, which continues to sit atop App Store lists.

So what, if anything, could Instagram do differentiate itself? Unlike before, ‘add filters’ doesn’t seem to be the answer here. Does it make the limit on clips longer than 6 seconds? Shorter than 6 seconds? Or do they just leave it all up to the user?

I’m also wondering if Instagram’s new video service will have a standalone app, or just be built into the current one. I guess we’ll find out all of this and more on Thursday. The event will be held at Facebook’s Menlo Park, California headquarters.

Coincidentally, the Vine team just posted this ‘Thank You’ video:

So, what do you think about the idea of an Instagram-run video sharing service?